Circuit breaker with blowing device



0ct. 2l,v 1947. M. J. GAY

CIRCUIT BREAKER WITH BLOWING DEVICE [n1/en o'r Amun/cf .mo/v 64 Y FiledI July 27, 1943 .tarn ey.

Patented Oct. 2l, 1947 2,429,311 CIRCUIT BREAKER WITH BLOWING DEVICE Maurice Jean Gay, Villeurbanne, France; vested in the Attorney General of the United States Application July 27, 1943, Serial No. 496,285

This invention relates to circuit breakers and more particularly to breakers having auxiliary means for extinguishing the arc formed on separation of the contacts.

In prior devices of this character means has been provided for forming a chamber enclosing the arc gases and utilizing the expansive force of such gases to extinguish or blow out the arc and such devices have also been provided with mechanically operated means for assisting in the blowing out of the arc. Many of such devices are, however, subject to certain disadvantages. Where, for example, a blowing jet of gas is produced by such means, throughout the entire movement of separation of the contacts, it is obvious that during the initial separation of the contact, the jet is ineffectual in extinguishing the arc, and the energy expended in producing the jet during such initial period is Wasted. Also, many of such devices tend to produce excessive gas pressure which may result in the formation of ignition arcs across the supply network.

Among the objects of the present invention is to avoid the disadvantages above noted and to provide `an apparatus for ysupplying to the arc an'ample ilow of arc extinguishing fluid under a suficient and constant but not excessive pressure.

In accordance with my invention, I provide a means for limiting the pressure under which the extinguishing fluid is injected into the arc which means is independent rof :the movement of the contacts.r The extinguishing ilud is preferably delivered from the compression chamber the volurne of which is expansible under excessive internal pressure so Aas to insure the delivery of the iluid under constant pressure.

Other objects of my invention willappear from the following description taken in connection with the accompanying drawing wherein:

Figs. 1 and 2 are vertical sectional views partly in elevation showing the movable contact assembly adapted for immersion in an arc extinguishing liquid such as oil, with themovable contact inthe respective gures shown in extended and retracted positions, and

Fig, 3 is a side elevation, partly insection, of a switch embodying a contact assembly similar to that shown in Figs. 1 and 2 but adapted for pneumatic operation.

The pump shown in the drawing is formed by a movable piston 2| and a semi-fixed piston 22. The piston can slide in the xed connection 30 which supports the upper end of its rod 28 in the circuit closing position of the circuit-breaker..

In the vform of invention shown in Figs. 1 and 2,

France November 14, 1941 l5 claims. (c1. 20o-148) the connection 30 is supported by a casing 40 adapted to contain oil in which the movable contact operates. A compensating spring 29 is inserted between connection 30 and piston 22 and tends to keep the latter in its position of rest, that is to say: in lower position. This piston cooperates with cylinder 2| concentrically guided around the axle of the piston by rods 4| threaded through the supportr 30 and is subject to the action of a spring 21 which is placed between the piston and the bottom of this cylinder 25. Spring 21 tends to lower the cylinder in its extreme position, shown in Fig. 3, in which it is stopped by any suitable means (not shown).

The bottom 2|) of the cylinder is perforated, having several openings 25 through which a blowing-out nozzle 26 united with this bottom of cylinder is fed by a liquid set under pressure in the cylinder.

On the common axis of this pump 2|-22 the solid rod 23 of the movable electrode 24 is placed.

During a certain portion of its stroke, this rod can slide freely through the cylinder and the piston. However, as the electrode 24 has a larger diameter than rod 23, it carries away along a portion of its upward stroke the cylinder 22, compressing spring 21. f The working of the hereabove described device is as follows: at the moment of the interrupting of the circuit breaker, the electrode 24, the rod 23 of which is pulled upward by driving device which is not shown, rises at rst freely from its circuit-closing position represented in Fig. 1 in which it engages a' fixed contact (not shown) until it hits the bottom rof cylinder 20, at the very moment when the complementatry blowingout of the arc can eiiciently begin. Then, driven away by the upward motion of the electrode, the cylinder rises and the piston 22 being held stationary under the action of spring 29, the elective volumeof the cylinder 2| lessens so that the liquid it contains is set under pressure and passes through openings 25 in nozzle 26, from where it is injected in the arc. When the pressure insideA the cylinder tends to become too great, the compensating spring 29 is compressed and the piston rises, so that the pressure in the cylinder is maintained almost constant during a rather long space of time and near the end of its stroke.

It will be noticed that the spring`29 has acted once more as amotion-damper. Also, it must be pointed out that the oil quantity set under pressure by this pump may be very important as theV entire pump is quite independent of the movable contact entering the non represented extinguishing pot. Also, as the movable electrode-rod is solid it has greater rigidity than a tube and may be made of a light metal, instead of copper thus facilitating movement of the parts.

The pressure limiter conformable to the invention may be advantageously applied to circuitbreakers with blowing-by compressed gas in which the latter is supplied by a pump put in motion during the motion of the movable Contact.

ln some circuit breakers of this kind, it happens that at the end of the stroke of the movable contact, the blowing-out is made with a reduced pneumatic energy which is insufficient. This especially is prejudicial in relatively high-tension apparatuses, in which the blowing-out can only be eiiiciently made at the end of the movable contact-stroke, when the contacts are sufficiently separated one from the other.

However, the same disadvantages appear also in apparatuses in which the pump is used as a source of auxiliary blowing-out, intended for circuit-breaking of currents of less intensity, together with a second source of blowing-out having an energy which is ra function ofthe intensity of the arc and therefore insuicient for the interrupting of lower currents.

Fig. 3, as an example, shows this type of apparatus with pressure limiter applied to an auxiliary pump. The circuit breaker assembly shown in Fig. 3 is carried by an insulating base 45 having two contact carrying columns or posts 4S and 4l. Post 4'! carries the stationary contact assembly comprising a xed 'insulating tube 32 open at one end and adapted to receive the movable contact head 25;. Tube 32 is closed at the other end by the Contact 3| resiliently held in position by a spring 48. vContact hea-'d 24 is mounted at the end of a contact rod 23 which extends through a bearing 49 on the post 46 and is attached by a pin and slot connection to an operating arm 3 3 pivoted on the'base 4d. Spring fingers 5l in thebearing`49 press against the rod 23 and serve to make electrical contact therewith. `Surrounding and partly supporting the rod 23 is a piston 22 which is slidable in an upright extension 53 of the post 45, a spring 29 being interposed between the extension 53 and the piston head.

Surrounding the piston 22 and spring 29 is a cylinder 2| closed at one end by a perforated head 59 between which and the piston head is a spring 2. Cylinder 2| is s'lidable toward and away from the tube 32 being guided in its movement by rods 4 l which pass through openings in the extension 53 of the post 4e. Mounted on the forward end of the cylinder El' is a convergent nozzle 65 of insulating material.

The operation ofthe device shown in Fig. 3 is similar to that of Figs. l and 2. On separation of the contacts, contact 24' is retracted into the nozzle 6i) and on engagement with the cylinder head 59 retracts the cylinder 2l against the action of the spring 2l. Any excess gas pressure will cause the piston to move toward the left thereby increasing the volume of the enclosed gas space in the nozzle and cylinder.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that whatI claim is 1. An electric circuit breaker comprising a frame, a set of cooperating contact members, one of said members being stationary and the other one being slideably mounted in said frame for variation of their relative positions and constructed and arranged to engage said stationary contact member in the closed position of the circuit breaker, a pumping means adapted to blow an arc-extinguishing fluid into the arcing space between said contact members during the separating movement of the same, said pumping means including a movable pump cylinder and a plunger formed with an orifice throughout its whole length, said plunger being adapted to reciprocate with respect to and within said pump cylinder, said slideable contact member constituting a rod extending through said pump cylinder and said plunger and slideable in said plunger orifice, a loading means adapted to exert pressure in such direction and of such value on said plunger that said plunger is shifted to increase the volume of the active space within said cylinder, when a predetermined pressure of the arcextinguishing fluid is exceeded, whereby said plunger acts as a pressure relieving and equalizing means.

2. An electric circuit breaker, according to claim l, wherein that extremity of said slideable contact rod which extends beyond said Cylinder and engages said stationary contact member is provided with a protruding portion being constructed and arranged to engage a part of said cylinder, when said slideable contact rod is retracted from said stationary contact member during the opening movement of the circuit breaker, whereby said slideable contact rod moves said cylinder towards said plunger-and thereby operates said pumping means.

3. An electric circuit breaker according to claim l, wherein a spring means is inserted between said plunger and said cylinder, said spring means being constructed and arranged to urge said cylinder away from said plunger, thus restoring said pumping means to its initial position, when said contact rod is moved into engagement with said stationary contact member.

4. An electric circuit breaker, according to claim 1, wherein that extremity of said slideable contact rod which extends beyond said cylinder and engages said stationary contact member is provided with a protruding portion being constructed and arranged to engage a part of said cylinder, while said slideable contact rod is retracted from said stationary contact member of saidset during the opening movement of the circuit breaker, whereby said slideable contact rod moves said cylinder towards said plunger and thereby operates said pumping means, and wherein a discharge nozzle for the arc-extinguishing uid is provided at that extremity of the cylinder which faces the arcing space between the contact members to be separated, said discharge nozzle having an opening at its free end and having such dimensions that the tip of the slideable contact member is retracted therein, when said protruding portion of said contact rod engages said cylinder part.

5. An electric circuit breaker comprising a frame, a set of cooperating contact members, at

' least one of said members being slideably mounted in said frame for variation of their relative positions and constructed and arranged to engage the other contact member in the closed position of the circuit breaker, a pumping means adapted to blow an arc-extinguishing uid into the arcing space between said contact members during the separating movement of the same, said pumping means including a movable pump cylinder and a plunger formed with an orifice throughout vits whole length, said plunger being adapted to reciprocate with respect to and within said pump cylinder, said slideable contact member constituting a rod extending through said pump cylinder and said plunger and slideable in said plunger orice, a loading means adapted to exert pressure in such direction and of such Value on said plunger that said plunger is shifted to increase the volume of the active space within said cylinder, when a predetermined pressure of the arc-extinguishing fluid is exceeded, whereby said plunger acts as a pressure relieving and equalizing means, that part of said slideable contact rod which extends beyond said cylinder and engages said other contact member being provided with a protruding portion being constructed and arranged to engage a part of said cylinder, when said slideable contact rod is retracted from the other contact member of said set during the opening movement of the circuit breaker, whereby said slideable contact rod moves said cylinder towards said plunger and thereby Operates said pumping means, a discharge nozzle for the arc-extinguishing fluid provided at that extremity of the cylinder which faces the arcing space between the contact members to be separated, said discharge nozzle having an opening at its free end through which the tip of said slideable Contact member can pass, said slideable Contact member, said discharge nozzle, said protruding portion and said cylinder part being so dimensioned and adapted that the protruding portion engages said cylinder part when said contact member tip passes said nozzle opening during its retracting movement.

MAURICE JEAN GAY.

REFERENCES CITED The following references are of record in the file ci this patent:

UNITED STATES PATENTS Number Name Date 2,084,936 Bresson June 22, 1937 2,095,441 Howe Oct. 12, 1937 2,265,232 Hoffer Dec. 9, 1941 2,051,659 Uebermuth Aug. 18, 1936 FOREIGN PATENTS Number Country Date 636,024 Germany Oct. 1, 1936 

